Electronic expansion valve

ABSTRACT

An electronic expansion valve includes the valve needle screw assembly which also includes an outer edge guide section, the electronic expansion valve includes an inner edge guide section matched with the outer edge guide section, in the process of the action of the valve needle of the electronic expansion valve, the outer edge guide section of the valve needle screw assembly is matched with the inner edge guide section of the electronic expansion valve, to provide the guide for the valve needle, relatively reducing the deviation of the valve needle relative to the valve port, thereby reducing the eccentric wear of the valve needle.

CROSS-REFERENCED APPLICATIONS

The present application is the National Stage Application of International Application No. PCT/CN2020/098380, filed on Jun. 28, 2020, which claims the priority to Chinese Patent Application No. 201910574593.5, titled “ELECTRONIC EXPANSION VALVE”, filed with the China National Intellectual Property Administration on Jun. 28, 2019, the entire disclosures of which are incorporated in their entireties herein by reference.

BACKGROUND 1. Field of the Disclosure

The present application relates to the technical field of refrigeration control, and particularly to an electronic expansion valve.

2. Discussion of the Background Art

An electronic expansion valve is mainly used in variable frequency air conditioning system. The rotation of a stepping motor rotor is controlled by an electronic controller. Through the transmission of the nut and the screw rod, the valve needle is driven to move axially relative to the valve port, thereby adjusting the flow area of the valve port to realize the automatic adjustment of the refrigerant flow.

If the valve needle deviates from the valve port, it is easy to cause eccentric wear of the valve needle, which may affect the working effect of the electronic expansion valve.

Therefore, an electronic expansion valve needs to be designed, in which the valve needle of the electronic expansion valve is not easy to deflect with respect to the valve port.

SUMMARY

An object of the present application is to provide an electronic expansion valve, the valve needle of the electronic expansion valve is not easy to deflect with respect to the valve port.

To achieve the above object, the following technical solutions are provided in the present application.

An electronic expansion valve, includes a valve needle screw rod assembly; the valve needle screw rod assembly includes a valve needle, a valve needle sleeve, and a screw rod assembly;

the valve needle is fixedly connected to the valve needle sleeve, the valve needle sleeve includes a peripheral wall portion and a matching portion, an inner diameter of the matching portion is smaller than an inner diameter of the peripheral wall portion;

the screw rod assembly includes a valve needle support portion, the valve needle support portion includes a valve needle support washer or a suspension engagement portion or a sleeve washer, the valve needle support washer or the suspension engagement portion or the sleeve washer may abut against the matching portion of the valve needle sleeve;

the valve needle screw rod assembly further includes an outer edge guide section, the electronic expansion valve includes an inner edge guide section that cooperates with the outer edge guide section.

In the electronic expansion valve provided by the present application, during the movement of the valve needle, the outer edge guide section of the valve needle screw rod assembly cooperates with the inner edge guide section of the electronic expansion valve to provide guidance for the valve needle. This relatively reduces the deviation of the valve needle relative to the valve port, thereby reducing the eccentric wear of the valve needle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully closed state;

FIG. 2 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully open state;

FIG. 3 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application when the valve needle and the valve port sealing portion just contact;

FIG. 4 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application when the spring has not been further compressed at the critical point;

FIG. 5 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully closed state;

FIG. 6 is a cross-sectional view of the valve needle screw rod assembly in FIG. 1;

FIG. 7 is an exploded view of the valve needle screw rod assembly in FIG. 6;

FIG. 8 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

FIG. 9 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

FIG. 10 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

FIG. 11 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

FIG. 12 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

FIG. 13 is a partial cross-sectional view of the second embodiment of the electronic expansion valve provided by the present application in a fully open state;

FIG. 14 is a partial cross-sectional view of the third embodiment of the electronic expansion valve provided by the present application in a fully open state;

FIG. 15 is a partial cross-sectional view of the fourth embodiment of the electronic expansion valve provided by the present application in a fully open state;

FIG. 16 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

FIG. 17 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

The above drawings include the following reference numerals:

1 valve needle screw rod assembly; 11 valve needle; 111 valve needle sealing portion; 112 valve needle upper guide section; 113 stepped portion; 114 valve needle lower guide section; 12 valve needle sleeve; 121 matching portion; 122 peripheral wall portion; 13 spring washer portion; 14 spring; 15 screw rod assembly; 16 outer edge guide section; 151 screw rod; 1511 lower groove portion of spring; 1512 valve needle support groove portion; 1513 valve needle support flange portion; 1514 annular groove on spring; 153 lower stop portion; 1531 lower flange portion; 154 valve needle support portion; 1541 valve needle support washer; 155 upper stop portion; 1551 upper flange portion; 1552 upper retaining ring; 156 bushing part; 1561 connecting hole portion; 1562 body portion; 1563 suspension engagement portion; 20 valve body; 2 valve seat assembly; 2A inner edge guide section; 21 valve seat; 211 valve port; 2111 valve port sealing portion; 212 inner hole guide portion; 22 first connecting pipe portion; 23 second connecting pipe portion; 24 guide seat; 241 small inner edge guide section; 25 connecting seat; 3 nut assembly; 31 nut; 32 nut connecting portion; 33 slip ring; 4 rotor assembly; 41 rotor magnet; 42 rotor connecting portion; 43 rotor stop portion; 5 outer shell; 30 stator coil;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In order to provide those skilled in the art a better understanding of the solutions of the present application, the present application is described hereinafter in further detail in conjunction with the drawings and embodiments.

Referring to FIGS. 1 to 7, FIG. 16, FIG. 1 is a cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully closed state; FIG. 2 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully open state; FIG. 3 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application when the valve needle and the valve port sealing portion just contact; FIG. 4 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application when the spring has not been further compressed at the critical point; FIG. 5 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully closed state; FIG. 6 is a cross-sectional view of the valve needle screw rod assembly in FIG. 1; FIG. 7 is an exploded view of the valve needle screw rod assembly in FIG. 6; FIG. 16 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state; FIG. 17 is a partial cross-sectional view of another valve needle screw rod assembly provided by the present application in a fully open state;

Specific reference is made to FIG. 1. FIG. 1 is a cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully closed state. In a specific embodiment, the electronic expansion valve provided by the present application includes a valve body 20 and a stator coil 30. The valve body 20 includes a valve needle screw rod assembly 1, a valve seat assembly 2, a nut assembly 3, a rotor assembly 4 and an outer shell 5. The stator coil 30 of the electronic expansion valve is connected to the drive controller. After the drive controller is energized, a pulse drive signal is sent to the stator coil 30. The stator coil 30 generates a periodically changing magnetic field, thereby driving the rotor assembly 4 of the electronic expansion valve to rotate in a forward direction or a reverse direction. The rotor assembly 4 is fixedly connected with the screw rod 151 of the valve needle screw rod assembly 1. When the rotor assembly 4 rotates, it synchronously drives the screw rod 151 to rotate. The screw rod 151 of the valve needle screw rod assembly 1 is provided with an external thread, and an inner hole of the nut 31 of the nut assembly 3 is provided with an internal thread. The screw rod 151 is threadedly engaged with the nut 31, and when the rotor assembly 4 rotates, the screw rod 151 moves along the axial direction, thus driving the valve needle screw rod assembly 1 to move close to or far away from the valve port 211.

Referring to FIG. 1, the valve seat assembly 2 provided in this embodiment includes a valve seat 21, a first connecting pipe portion 22, a second connecting pipe portion 23, a guide seat 24 and a connecting seat 25, The first connecting pipe portion 22, the second connecting pipe portion 23, the guide seat 24 and the connecting seat 25 are fixedly assembled with the valve seat 21. Specifically, the first connecting pipe portion 22 and the second connecting pipe portion 23 are fixedly connected to the valve seat 21, and the fluid medium may flow out of the second connecting pipe portion 23 from the first connecting pipe portion 22 through the valve seat 21. Of course, the fluid medium may also flow from the second connecting pipe portion 23 through the valve seat 21 and then out of the first connecting pipe portion 22.

The first connecting pipe portion 22 and the second connecting pipe portion 23 serve as the inflow or outflow channel of the fluid medium of the electronic expansion valve, and are generally used for connecting with the system pipeline when the electronic expansion valve is mounted in a refrigeration or heating system such as an air conditioner. The valve seat 21 is provided with a valve port 211 at a position close to the center of the second connecting pipe portion 23, and a valve port sealing portion 2111 is provided on an upper edge of the valve port 211.

A center inner hole position of the guide seat 24 of the valve seat assembly 2 is provided with an inner edge guide section 2A that matches with an outer wall of the valve needle screw rod assembly 1. When the electronic expansion valve is opened or closed, the inner edge guide section 2A provides a guiding function for the valve needle screw rod assembly 1.

An upper side of the valve seat assembly 2 is coaxially provided with a nut assembly 3. The nut assembly 3 includes a nut 31, a nut connecting portion 32, a slip ring 33 and a spiral guide 34. The nut 31 may be fixedly connected to the valve seat assembly 2 through the nut connecting portion 32 by welding or the like. In this embodiment, the nut connecting portion 32 is welded to the connecting seat.

A slip ring 33 and a spiral guide 34 are provided on an outer edge, towards the upper side, of the nut 31. The slip ring 33 may spirally rotate along the spiral guide 34 within the upper and lower stroke limits. The slip ring 33 and the spiral guide 34 cooperate with the rotor assembly 4 to realize the stroke control of the electronic expansion valve from fully opening to fully closing.

Referring to FIG. 1, the rotor assembly 4 includes a rotor magnet 41, a rotor connecting portion 42, and a rotor stop portion 43 (the rotor stop portion 43 and the rotor magnet 41 may be integrally formed, in this embodiment, a separate assembly method is adopted). The rotor assembly 4 may be fixedly connected to the screw rod 151 of the valve needle screw rod assembly 1 through the rotor connecting portion 42 (for example, welding connection may be adopted), The rotor assembly 4 is driven by the stator coil 30 to drive the screw rod 151 to rotate synchronously. A rotor stop portion 43 is provided inside the rotor assembly 4. The rotor stop portion 43 cooperates with the slip ring 33 on the nut 31 and the spiral guide 34 to limit the rotation of the rotor assembly 4 within a prescribed stroke range.

In addition, the electronic expansion valve provided in this embodiment further includes an outer shell 5 having an open end, the outer shell 5 is mounted outside the rotor assembly 4. The opening of the outer shell 5 and the connecting seat 25 on the upper side of the valve seat assembly 2 are welded and sealed to form a closed accommodating cavity.

The valve needle screw rod assembly 1 mainly includes a valve needle 11, a valve needle sleeve 12, a spring washer portion 13, a spring 14 and a screw rod assembly 15. Specific reference can be mad to FIG. 6 and FIG. 7. FIG. 6 is a cross-sectional view of the valve needle screw rod assembly; FIG. 7 is an exploded view of the valve needle screw rod assembly;

The valve needle 11 and the valve needle sleeve 12 may be fixedly connected by welding, etc. One end of the valve needle 11 includes a valve needle sealing portion 111 for cooperating with the valve port sealing portion 2111 to close the valve port 211. The valve needle sleeve 12 includes a peripheral wall portion 122 located on its outer periphery and a matching portion 121 integrally formed with the peripheral wall portion 122. Of course, the peripheral wall portion 122 and the matching portion 121 may also be fixedly connected by welding, clamping, etc.. In addition, an inner diameter of the peripheral wall portion 122 is larger than an inner diameter of the matching portion 121. The valve needle 11 and the valve needle sleeve 12 form an accommodating cavity A after being fixedly connected. Therefore, the valve needle 11 and the valve needle sleeve 12 define the accommodating cavity A.

In this embodiment, the valve needle 11 includes a valve needle upper guide section 112. After the valve needle 11 and the valve needle sleeve 12 are fixedly connected, the outer edges of the valve needle 11 and the valve needle sleeve 12 may be matched with an inner wall of the guide seat 24 at the same time. The valve needle 11 and the peripheral wall portion 122 of the valve needle sleeve jointly define the outer edge guide section 16. The outer edge guide section 16 is located on the valve needle upper guide section 112 of the valve needle 11 and the outer wall of the peripheral wall portion 122.

Of course, when there is a difference between the outer diameter of the valve needle upper guide section 112 and the peripheral wall portion 122, the part that matches with the inner wall of the guide seat 24 may also change. For example, when the inner diameter of the outer wall of the valve needle upper guide section 112 is larger than the inner diameter of the outer wall of the peripheral wall portion 122, only the valve needle upper guide section 112 is in guide fit with the guide seat 24. At this time, the guiding function of the valve needle screw rod assembly 1 is ensured by the valve needle upper guide section 112 and the inner edge guide section 2A of the guide seat 24. At this time, the valve needle upper guide section 112 defines the outer edge guide section 16.

Similarly, when the inner diameter of the outer wall of the peripheral wall portion 122 is larger than the inner diameter of the outer wall of the valve needle upper guide section 112, there is only the guide fit between the peripheral wall portion 122 and the guide seat 24. At this time, the guiding function of the valve needle screw rod assembly 1 is ensured by the peripheral wall portion 122 and the inner edge guide section 2A of the guide seat 24. At this time, the peripheral wall portion 122 defines the outer edge guide section 16.

In addition, in this embodiment, the valve needle 11 further includes a valve needle lower guide section 114. An outer diameter of the valve needle lower guide section 114 is smaller than an outer diameter of the valve needle upper guide section 112. In addition, the guide seat 24 is further provided with a small inner edge guide section 241 that cooperates with the valve needle lower guide section 114.

The small inner edge guide section 241 extends substantially along the inner wall of the guide seat 24 toward the center of its circle, so as to cooperate with the valve needle lower guide section 114.

Therefore, in this embodiment, at least one of the valve needle upper guide section 112 and the peripheral wall portion 122 defines the outer edge guide section 16.

In order to ensure the guiding effect between the outer edge guide section 16 and the inner edge guide section 2A, the inner diameter of the outer edge guide section 16 may be set to be larger than the inner diameter of the inner edge guide section 2A, and the outer diameter of the outer edge guide section 16 is 0.02 mm-0.15 mm greater than the inner diameter of the inner edge guide section 2A. Similarly, the inner diameter of the small inner edge guide section 241 is larger than the outer diameter of the valve needle lower guide section 114 by 0.02-0.05 mm. In addition, in this embodiment, the nut 31 further includes a nut guide section 311, and the nut guide section 311 is mounted outside the guide seat 24. The inner wall of the nut guide section 311 cooperates with the outer wall of the guide seat 24.

In addition, specific reference can be made to FIG. 16, and in FIG. 16, the peripheral wall portion 122 of the valve needle sleeve 12 may further extend upward. Therefore, the height of the peripheral wall portion 122 is not further limited in the present application.

The spring washer portion 13 provided in this embodiment may adopt a combination of an open retaining ring and a washer. That is, in this embodiment, the spring washer portion 13 includes both an open retaining ring and a washer. Of course, starting from the functional principle of the present application, the opening retaining ring of the spring washer portion 13 in this embodiment is not limited to the C-shaped opening retaining ring shown in the figure, and other shapes of opening retaining rings may also be used instead; similarly, the washer in this embodiment is not limited to the circular ring-shaped washer in the figure, and may also be replaced by other retaining rings that play the same role, for example, an open retaining ring may also be used instead.

In this embodiment, when the valve needle sleeve 12, fixedly connected to the valve needle 11, and the screw rod 151 rotate relative to each other, their rotational friction fit surfaces are mainly the upper and lower surfaces of the opening retaining ring, or the upper and lower surfaces of the washer. In order to further reduce the frictional resistance of its relative rotation, it is preferable to spray or plate a coating with lubricating and wear-resistant functions on its surface (for example, a coating containing polytetrafluoroethylene, or containing graphite, or containing molybdenum disulfide), thereby increasing the service life of the electronic expansion valve.

The screw rod assembly 15 includes a lower stop portion 153, and the lower stop portion 153 abuts against the spring washer portion 13. Specifically, in this embodiment, the screw rod 151 includes a lower groove portion 1511 of spring, and the lower groove portion 1511 of spring is formed by the recessing of the surface of the screw rod 151. The screw rod assembly 15 forms a lower flange portion 1531. In this embodiment, the lower stop portion 153 is the lower flange portion 1531.

In the lower groove portion 1511 of spring, a spring washer portion 13 is provided. At this time, the spring washer portion 13 is connected with the lower groove portion 1511 of spring with the position thereof being limited.

It is worth noting that the lower flange portion 1531 may also be formed in different ways. For example, the screw rod 151 does not include the lower groove portion 1511 of spring, and the lower flange portion 1531 may be formed by the lower end of the screw rod 151 extending in the circumferential direction of the surface thereof. The lower flange portion 1531 may still abut against the spring washer portion 13.

In addition, the screw rod assembly 15 further includes an upper stop portion 155, and the upper stop portion 155 abuts against the spring 14. Specifically, in this embodiment, the screw rod assembly 15 includes an upper flange portion 1551, and the upper flange portion 1551 extends circumferentially along the surface of the screw rod 151. The upper flange portion 1551 and the screw rod 151 may be integrally formed, or they may be fixedly connected by welding, etc.. In this embodiment, the upper stop portion 155 is the upper flange portion 1551.

In addition, the spring 14 is further mounted around the screw rod 151. Specifically, one end of the spring 14 abuts against the upper flange portion 1551, and another end of the spring 14 abuts against the spring washer portion 13. Under the action of the spring 14, the spring washer portion 13 abuts the lower flange portion 1531. It is worth noting that one end of the spring 14 abuts against the upper flange portion 1551, which means that one end of the spring 14 may directly abut against the upper flange portion 1551, or one end of the spring 14 may indirectly abut against the upper flange portion 1551. For example, the spring 14 and the upper flange portion 1551 are directly provided with a retaining ring or other components.

Since the spring washer portion 13 is connected with the lower groove portion of spring 1511 with the position thereof being limited, the spring washer portion 13 abuts against the lower flange portion 1531 due to the influence of the spring 14 on the spring washer portion 13.

In the electronic expansion valve provided in this embodiment, the spring 14 is mounted around the screw rod 151, and the upper end of the spring 14 abuts against the upper stop portion 155, and the lower end of the spring 14 abuts against the lower stop portion 153 by the spring washer portion 13. The cooperation of the spring 14 and the screw rod assembly 15 may relatively reduce the deflection of the spring 14, thereby reducing eccentric wear.

In addition, the valve needle screw rod assembly 1 provided by this embodiment further includes a valve needle support portion 154, and the valve needle support portion 154 abuts against the matching portion 121. Specifically, in this embodiment, the screw rod assembly 15 includes a bushing part 156. The bushing part 156 includes a connecting hole portion 1561, a body portion 1562, and a suspension engagement portion 1563. The connecting hole portion 1561 may be a through hole or a blind hole, one end of the screw rod 151 and the connecting hole portion 1561 may be fixedly connected by welding, interference fit, or the like.

The suspension engagement portion 1563 extends along the circumferential direction of the body portion 1562, and the outer diameter of the suspension engagement portion 1563 is larger than the outer diameter of the body portion 1562. In this embodiment, the valve needle support portion 154 is the suspension engagement portion 1563, and the outer diameter of the suspension engagement portion 1563 is larger than the inner diameter of the matching portion 121.

In addition, when the valve port 211 is fully opened or the like, a distance D1 between the suspension engagement portion 1563 and the first retaining ring is greater than or equal to a distance D2 between the suspension engagement portion 1563 and the upper end of the matching portion 121.

The distance between D1-D2 may be between 0-0.03 mm.

The valve needle 11 may be suspended on the suspension engagement portion 1563 through the valve needle sleeve 12. Since the valve needle 11 is suspended on the suspension engagement portion 1563 through the valve needle sleeve 12, the valve needle 11 is not subjected to the elastic load generated by the spring 14.

Please refer specifically to FIG. 2, FIG. 2 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully open state. When the electronic expansion valve is in the fully open state, the stroke of the valve needle 11 from the valve port 211 is L. At this time, the valve needle screw rod assembly 1 is at the uppermost end of its stroke, and the spring 14 is in its initial compression state. The slidable spring washer portion 13 provided on the valve needle screw rod assembly 1 abuts on the upper surface of the lower flange portion 1531, and the valve needle 11 is not subjected to the elastic load generated by the spring 14. The valve needle 11 is suspended on the suspension engagement portion 1563 through the valve needle sleeve 12. A lower surface of the spring washer portion 13 abuts against the upper surface of the lower flange portion 1531. At this time, there is still a certain amount of clearance D1-D2 between the lower surface of the spring washer portion 13 and the upper surface of the matching portion 121, so the valve needle 11 is not subjected to the elastic load generated by the spring 14. The valve needle 11 is suspended and supported by the suspension engagement portion 1563 of the bushing part 156.

In addition, as the rotor assembly 4 rotates, the screw rod 151 moves along the axial direction, and the distance between the valve needle sealing portion 111 of the valve needle 11 and the valve port sealing portion 2111 of the valve port 211 may also change.

Specific reference can be made to FIG. 3. FIG. 3 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application when the valve needle and the valve port sealing portion just contact; the electronic expansion valve moves from the fully open state until the valve needle sealing portion 111 just touches the valve port sealing portion 2111. At this time, the displacement of the valve needle 11 is L, and the spring 14 is always in its initial compressed state. The lower stop portion 153 provided on the screw rod 151 always abuts against the lower flange portion 1531 of the screw rod assembly 15; the valve needle 11 is also not subjected to the elastic load generated by the compression spring 14 in this state. The lower surface of the spring washer portion 13 and the upper surface of the matching portion 121 of the valve needle sleeve 12 still maintain a certain amount of clearance D1-D2.

Specific reference can be made to FIG. 4. FIG. 4 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application when the spring has not been further compressed at the critical point. Compared with the state in FIG. 3, the screw rod 151 in FIG. 4 continues to move downward by the displacement amount of D1-D2. At this time, the lower surface of the spring washer portion 13 and the upper end of the matching portion 121 of the valve needle sleeve 12 are just at the critical point of contact, which is equivalent to the spring 14 being at the critical point to be further compressed, and is also equivalent to the valve needle 11 and the valve needle sleeve 12 being at the critical point to withstand the elastic load of the compression spring 14 that is further compressed.

Specific reference can be made to FIG. 5. FIG. 5 is a partial cross-sectional view of the first embodiment of the electronic expansion valve provided by the present application in a fully closed state. Compared with the state in FIG. 4, the screw rod 151 in FIG. 5 is moved downward by a displacement amount of α. The lower surface of the spring washer portion 13 and the matching portion 121 of the valve needle sleeve 12 have been pressed tightly, and the spring 14 has been further compressed. The valve needle sealing portion 111 of the valve needle screw rod assembly 1 and the valve port sealing portion 2111 of the valve seat assembly 2 are in contact and pressed tightly. The spring washer portion 13 provided on the screw rod 151 abuts against the upper surface of the matching portion 121 of the valve needle sleeve 12, and the valve needle 11 is loaded by the elastic force generated by the spring 14 that is further compressed. The electronic expansion valve is in a fully closed state, the screw rod 151 is at the lowest end position of its stroke, and the downward stroke of the screw rod 151 from the fully opening state to the fully closing state is L+α+D1−D2.

Specific reference can be made to FIG. 8. FIG. 8 is a partial cross-sectional view of another valve needle screw rod assembly in a fully open state. The screw rod assembly 15 includes a lower stop portion 153, and the lower stop portion 153 may abut against the spring washer portion 13. Specifically, the screw rod assembly 15 includes a bushing part 156. The bushing part 156 includes a connecting hole portion 1561, a body portion 1562, and a suspension engagement portion 1563. The connecting hole portion 1561 may be a through hole or a blind hole, one end of the screw rod 151 and the connecting hole portion 1561 may be fixedly connected by welding, interference fit, or the like.

The suspension engagement portion 1563 extends along the circumferential direction of the body portion 1562, and the outer diameter of the suspension engagement portion 1563 is larger than the outer diameter of the body portion 1562. In this embodiment, the valve needle support portion 154 is the suspension engagement portion 1563, and the outer diameter of the suspension engagement portion 1563 is larger than the inner diameter of the matching portion 121. Therefore, the suspension engagement portion 1563 may abut against the matching portion 121 of the valve needle sleeve 12.

In addition, the lower stop portion 153 of the valve needle screw assembly 1 is no longer the lower flange portion 1531. The lower stop portion 153 is the body portion 1562 of the bushing part 156. That is, in this embodiment, the body portion 1562 and the spring washer portion 13 may abut against each other.

It is worth noting that the “may” mentioned in the present application refers to a specific state, but does not mean that the electronic expansion valve is in all working states. For example, in this embodiment, the body portion 1562 may abut against the spring washer portion 13, which means that the valve port 211 is fully opened or the like.

Of course, at this time, the distance D1 between the suspension engagement portion 1563 and the first retaining ring and the distance D2 between the suspension engagement portion 1563 and the upper end of the matching portion 121 still satisfy D1≥D2.

Specific reference can be made to FIG. 9. FIG. 9 is a partial cross-sectional view of another valve needle screw rod assembly in a fully open state.

The screw rod assembly 15 includes a valve needle support portion 154, and the upper surface of the valve needle support portion 154 may abut against the matching portion 121 of the valve needle sleeve 12. Specifically, the screw assembly 15 includes a valve needle support washer 1541. In addition, a valve needle support groove portion 1512 and a valve needle support flange portion 1513 are also provided on the screw rod 151. The valve needle support groove portion 1512 is formed by the recessing of the surface of the screw rod 151. Thus, the valve needle support flange portion 1513 located below the valve needle support groove portion 1512 protrudes relative to the circumferential direction of the valve needle support groove portion 1512. The valve needle support washer 1541 is assembled in the valve needle support groove portion 1512. Specifically, the valve needle support washer 1541 and the valve needle support groove portion 1512 are fixedly connected or connected with the position thereof being limited.

It is worth noting that the molding method of the valve needle support flange portion 1513 may also adopt other forms. For example, the screw rod 151 is not provided with the valve needle support groove portion 1512. The valve needle support flange portion 1513 may be formed by a position close to the lower end of the screw rod 151 extending in the circumferential direction of its surface. At this time, the valve needle support flange portion 1513 may still abut against the valve needle support washer 1541.

At this time, the valve needle support portion 154 is a valve needle support washer 1541, and the upper surface of the valve needle support washer 1541 may abut against the matching portion 121 of the valve needle sleeve 12. When the valve port 211 is opened or the like, the valve needle 11 may be supported by the valve needle support washer 1541 via the valve needle sleeve 12 fixedly connected to it.

The difference from the first embodiment is that in this embodiment, the valve needle support portion 154 is no longer a suspension engagement portion 1563, and the valve needle support portion 154 is the valve needle support washer 1541. That is to say, in this embodiment, the matching portion 121 and the valve needle support washer 1541 may abut against each other.

It is worth noting that the “may” mentioned in the present application refers to a specific state, but does not mean that the electronic expansion valve is in all states. For example, in this embodiment, the matching portion 121 and the valve needle support washer 1541 may abut against each other, which means that the valve port 211 is fully opened or the like.

Of course, at this time, the distance D1 between the valve needle support washer 1541 and the first retaining ring and the distance D2 between the valve needle support washer 1541 and the upper end of the matching portion 121 still satisfy D1≥D2.

In order to further reduce the rotational frictional resistance of the matching portion 121 relative to the screw rod 151, a coating with lubricating and wear-resisting functions (such as a coating containing polytetrafluoroethylene, graphite or molybdenum disulfide) may be sprayed or plated on the surface of the valve needle support washer 1541, so as to prolong the service life of the electronic expansion valve.

Specific reference can be made to FIG. 10. FIG. 10 is a partial cross-sectional view of another valve needle screw rod assembly in a fully open state; the screw rod assembly 15 includes an upper stop portion 155, and the upper stop portion 155 abuts against the spring 14. Specifically, in this embodiment, the screw rod assembly 15 is equipped with an upper retaining ring 1552. In addition, the screw rod 151 is further provided with an annular groove on spring 1514. The annular groove on spring 1514 is recessed along the surface of the screw rod 151. The upper retaining ring 1552 is assembled in the annular groove on spring 1514. Specifically, the upper retaining ring 1552 is fixedly connected with the annular groove on spring 1514 or connected with the annular groove on spring 1514 with the position thereof being limited, that is, it is clamped into the annular groove on spring 1514 for being limited.

The upper stop portion 155 is no longer an upper flange portion 1551. The upper stop portion 155 is an upper retaining ring 1552. That is, in this embodiment, the upper retaining ring 1552 abuts against the spring 14.

At this time, the spring 14 is mounted around the shaft of the screw rod 151, and the upper end of the spring 14 abuts against the lower end surface of the upper retaining ring 1552. It is worth noting that the present application does not limit the number of retaining ring in the upper retaining ring 1552. Specifically, the upper retaining ring 1552 provided on the annular groove on spring 1514 of the screw rod 151 may be composed of an open retaining ring, or one or more retaining rings may be added on the lower side of the open retaining ring.

Of course, at this time, the distance between the suspension engagement portion 1563 and the lower flange portion 1531 is D1, and the distance between the suspension engagement portion 1563 and the upper end of the matching portion 121 is D2, which still satisfies D1≥D2.

In this embodiment, when the valve needle 11 and the screw rod 151 rotate relative to each other, the rotating friction surfaces may also be the upper end of the spring 14 and the upper retaining ring 1552. In order to further reduce the frictional resistance of its relative rotation, a coating with lubricating and wear-resisting functions may be sprayed or plated on the surface of the upper retaining ring 1552 (for example, a coating containing polytetrafluoroethylene, or containing graphite, or containing molybdenum disulfide), thereby increasing the service life of the electronic expansion valve.

Specific reference can be made to FIG. 11. FIG. 11 is a partial cross-sectional view of another valve needle screw rod assembly in a fully open state; the number of the spring washer portion 13 of the valve needle screw rod assembly 1 is one. This embodiment illustrates that in the present application, the number of washers in the spring washer portion 13 is not limited.

In the electronic expansion valve provided in this embodiment, the spring 14 is mounted around the screw rod 151, and the upper end of the spring 14 abuts against the upper stop portion 155, and the lower end of the spring 14 abuts against the lower stop portion 153. The cooperation of the spring 14 and the screw rod assembly 15 may relatively reduce the deflection of the spring 14, thereby reducing eccentric wear.

Of course, at this time, the distance between the suspension engagement portion 1563 and the spring washer portion 13 is D1, and the distance between the suspension engagement portion 1563 and the upper end of the matching portion 121 is D2, which still satisfies D1≥D2.

Specific reference can be made to FIG. 12. FIG. 12 is a partial cross-sectional view of yet another valve needle screw rod assembly in a fully open state; in the valve needle screw rod assembly 1, a sleeve washer 157 is added between the bushing part 156 and the valve needle sleeve 12. When the valve needle 11 is not subjected to the elastic load generated by the spring 14, the valve needle 11 and the valve needle sleeve 12 are suspended on the suspension engagement portion 1563 of the bushing part 156 with a sleeve washer 157 being spaced apart.

At this time, the valve needle support portion 154 is the sleeve washer 157, and the upper surface of the sleeve washer 157 and the lower surface of the matching portion 121 of the valve needle sleeve 12 may abut against each other.

This embodiment illustrates that: in the present application, the upper end of the suspension engagement portion 1563 may abut against the matching portion 121 of the valve needle sleeve 12, and it is not limited to the direct abutment between the upper end of the suspension engagement portion 1563 and the matching portion 121 of the valve needle sleeve 12, but includes the indirect abutment between the upper end of the suspension engagement portion 1563 and the matching portion 121 of the valve needle sleeve 12.

Of course, at this time, the distance between the sleeve washer 157 and the spring washer portion 13 is D1, and the distance between the sleeve washer 157 and the upper end of the matching portion 121 is D2, which still satisfies D1≥D2.

In order to further reduce the rotational frictional resistance of the matching portion 121 of the valve needle sleeve 12 with respect to the screw rod 151. Preferably, a coating with lubricating and wear-resisting functions (such as a coating containing polytetrafluoroethylene, graphite or molybdenum disulfide) may be sprayed or plated on the surface of the sleeve washer 157, so as to prolong the service life of the electronic expansion valve.

Specific reference can be made to FIG. 17. FIG. 17 is a schematic structural diagram of another valve needle screw rod assembly; in the valve needle screw rod assembly 1, the structure of the valve needle 11 and the valve needle sleeve 12 is changed, and the valve needle includes a step portion 113, the peripheral wall portion 122 of the valve needle sleeve 12 is mounted outside the side surface of the step portion 113 and abuts against the step surface of the step portion 113, The matching portion 121 is an annular protrusion extending inwardly from the inner wall of the peripheral wall portion 122. In addition, compared with the above embodiment, the suspension engagement portion 1563 is located at the upper end of the bushing part 156 and is easier to engage with the matching portion 121 formed as above. At this time, the valve needle 11 and the valve needle sleeve 12 may be fixedly connected by welding, crimping, or the like.

Specific reference can be made to FIG. 13. FIG. 13 is a partial cross-sectional view of the second embodiment of the electronic expansion valve provided by the present application in a fully open state; it should be pointed out that the main object of the present application is to improve the valve needle screw rod assembly 1 of the electronic expansion valve. For other parts of the electronic expansion valve, such as the magnetic rotor assembly, the valve needle screw rod assembly, the nut assembly, the stop device, etc., general technology may be adopted, and other electronic expansion valve structures that may achieve the same function may also be adopted.

In order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function. The description of each component in the first embodiment is also applicable to the third embodiment, and the differences from the first embodiment are described in detail below.

For example, in this embodiment, the structure of the valve seat assembly 2 is slightly different. The valve seat assembly 2 is assembled and fixedly connected by the valve seat 21, the first connecting pipe portion 22, the second connecting pipe portion 23, and the guide seat 24. The nut assembly 3 in this embodiment is fixedly connected to the upper side of the valve seat 21 through the nut connecting portion 32, and the fixed connection method may preferably be a welding fixed connection.

In this embodiment, the valve needle 11 includes a valve needle upper guide section 112. After the valve needle 11 and the valve needle sleeve 12 are fixedly connected, the outer edges of the valve needle 11 and the valve needle sleeve 12 may be matched with an inner wall of the guide seat 24 at the same time. The valve needle 11 and the peripheral wall portion 122 of the valve needle sleeve 12 jointly define the outer edge guide section 16. The outer edge guide section 16 is located on the valve needle upper guide section 112 of the valve needle 11 and the outer wall of the peripheral wall portion 122.

Of course, when there is a difference between the outer diameter of the valve needle upper guide section 112 and the peripheral wall portion 122, the part that matches with the inner wall of the guide seat 24 may also change. For example, when the inner diameter of the outer wall of the valve needle upper guide section 112 is larger than the inner diameter of the outer wall of the peripheral wall portion 122, only the valve needle upper guide section 112 is in guide fit with the guide seat 24. At this time, the guiding function of the valve needle screw rod assembly 1 is ensured by the valve needle upper guide section 112 and the inner edge guide section 2A of the guide seat 24. At this time, the valve needle upper guide section 112 defines the outer edge guide section 16.

Similarly, when the inner diameter of the outer wall of the peripheral wall portion 122 is larger than the inner diameter of the outer wall of the valve needle upper guide section 112, there is only the guide fit between the peripheral wall portion 122 and the guide seat 24. At this time, the guiding function of the valve needle screw rod assembly 1 is ensured by the peripheral wall portion 122 and the inner edge guide section 2A of the guide seat 24. At this time, the peripheral wall portion 122 defines the outer edge guide section 16.

In the electronic expansion valve provided in this embodiment, the spring 14 is mounted around the screw rod 151, and the upper end of the spring 14 abuts against the upper stop portion 155, and the lower end of the spring 14 abuts against the lower stop portion 153. The cooperation of the spring 14 and the screw rod assembly 15 may relatively reduce the deflection of the spring 14, thereby reducing eccentric wear.

Reference can be made to FIG. 14. FIG. 14 is a partial cross-sectional view of the third embodiment of the electronic expansion valve provided by the present application in a fully open state; in order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function. The description of each component in the first embodiment is also applicable to the third embodiment, and the differences from the first embodiment are described in detail below.

In this embodiment, the valve seat assembly 2 is assembled and fixedly connected by the valve seat 21, the first connecting pipe portion 22 and the second connecting pipe portion 23. The center inner hole of the valve seat 21 of the valve seat assembly 2 is provided with an inner hole guide portion 212 that matches with the valve needle screw rod assembly 1. When the electronic expansion valve is opening or closing, the inner hole guide portion 212 of the valve seat 21 provides a guiding function for the valve needle screw rod assembly 1. Specifically, the inner hole guide portion 212 of the valve seat 21 cooperates with the outer edge of the valve needle 11 and/or the peripheral wall portion 122 of the valve needle sleeve 12 to provide guidance for the valve needle screw rod assembly 1.

In this embodiment, the valve seat assembly 2 includes the valve seat 21, the first connecting pipe portion 22, and the second connecting pipe portion 23. The first connecting pipe portion 22 and the second connecting pipe portion 23 are fixedly connected to the valve seat 21, and the fluid medium may flow out of the second connecting pipe portion 23 from the first connecting pipe portion 22 through the valve seat 21. Of course, the fluid medium may also flow from the second connecting pipe portion 23 through the valve seat 21 and then out of the first connecting pipe portion 22.

In addition, the valve seat 21 is further provided with an inner edge guide section 2A that cooperates with the valve needle screw rod assembly 1. At this time, the valve seat 21 defines the inner edge guide section 2A.

At this time, the guiding function of the valve needle screw rod assembly 1 is ensured by the outer edge guide section 16 and the inner edge guide section 2A of the valve seat 21.

Reference can be made to FIG. 15. FIG. 15 is a partial cross-sectional view of the fourth embodiment of the electronic expansion valve provided by the present application in a fully open state; in order to facilitate the description of this embodiment, the same reference numerals are used for the components in this embodiment and the first embodiment that have the same structure and have the same function. The description of each component in the first embodiment is also applicable to the third embodiment, and the differences from the first embodiment are described in detail below.

In this embodiment, the valve seat assembly 2 is assembled and fixedly connected by the valve seat 21, the first connecting pipe portion 22, the second connecting pipe portion 23, and the connecting seat 25. The first connecting pipe portion 22 is fixedly connected to the connecting seat 25, and the second connecting pipe portion 23 is fixedly connected to the valve seat 21. The inner edge guide portion 2A in this embodiment is provided on an inner hole wall on the upper side of the valve port 211 of the valve seat 21. The inner hole guide portion 212 of the valve seat assembly 2 provides a guiding function for the valve needle screw rod assembly 1. When the electronic expansion valve is opened and closed, the valve needle screw rod assembly 1 cooperates with the inner hole guide portion 212 of the valve seat assembly to realize the guiding and correcting function of the valve needle portion. Specifically, the inner hole guide portion 212 of the valve seat 21 cooperates with the outer edge of the valve needle 11 and/or the peripheral wall portion 122 of the valve needle sleeve 12 to provide guidance for the valve needle screw rod assembly 1.

In addition, in this embodiment, the nut 31 further includes a nut guide section 311, and the nut guide section 311 is mounted around the valve seat 21. The inner wall of the nut guide section 311 cooperates with the outer wall of the valve seat 21.

It should be noted that the orientation terms such as “up”, “down”, “left”, “right” mentioned in the embodiment are all introduced for the convenience of description based on the drawings in the description; and the ordinal terms such as “first” and “second” in the component name are also introduced for the convenience of description, and do not mean to make any restriction on any order of the components.

The electronic expansion valve according to the present application is described in detail hereinbefore. The principle and the embodiments of the present application are illustrated herein by specific examples. The above description of examples is only intended to help the understanding of the idea of the present application. It should be noted that, for the person skilled in the art, many modifications and improvements may be made to the present application without departing from the principle of the present application, and these modifications and improvements are also deemed to fall into the protection scope of the present application defined by the claims. 

What is claimed is:
 1. An electronic expansion valve, comprising a valve needle screw rod assembly, wherein the valve needle screw rod assembly comprises a valve needle, a valve needle sleeve, and a screw rod assembly; the valve needle is fixedly connected to the valve needle sleeve, the valve needle sleeve comprises a peripheral wall portion and a matching portion, an inner diameter of the matching portion is smaller than an inner diameter of the peripheral wall portion; the screw rod assembly comprises a valve needle support portion, the valve needle support portion is abutable against the matching portion of the valve needle sleeve; the valve needle screw rod assembly further comprises an outer edge guide section, the electronic expansion valve comprises an inner edge guide section that cooperates with the outer edge guide section.
 2. The electronic expansion valve according to claim 1, wherein the valve needle comprises a valve needle upper guide section, the outer edge guide section comprises at least part of the valve needle upper guide section and/or at least part of an outer wall of the peripheral wall portion of the valve needle sleeve.
 3. The electronic expansion valve according to claim 1, wherein the valve needle comprises a stepped portion, the stepped portion is fixedly connected to the valve needle sleeve, the outer edge guide section) comprises at least part of the outer wall of the peripheral wall portion.
 4. The electronic expansion valve according to claim 2, further comprising a valve seat assembly, wherein the valve seat assembly comprises a valve seat, a first connecting pipe portion, a second connecting pipe portion and a guide seat, the guide seat is fixedly connected with the valve seat, the guide seat defines the inner edge guide section, the first connecting pipe portion and the second connecting pipe portion are fixedly connected to the valve seat.
 5. The electronic expansion valve according to claim 4, wherein the valve needle further comprises a valve needle lower guide section, the guide seat comprises a small inner edge guide section that cooperates with the valve needle lower guide section.
 6. The electronic expansion valve according to claim 4, further comprising a nut assembly, wherein the nut assembly comprises a nut and a nut connecting portion, the nut is fixedly connected to the nut connecting portion, the nut further comprises a nut guide section, an inner wall of the nut guide section cooperates with an outer wall of the guide seat; the nut connecting portion is fixedly connected to the valve seat; or, the valve seat assembly further comprises a connecting seat, the connecting seat is fixedly connected to the valve seat, the nut connecting portion is fixedly connected to the connecting seat.
 7. The electronic expansion valve according to claim 2, further comprising a valve seat assembly, wherein the valve seat assembly comprises a valve seat, a first connecting pipe portion , a second connecting pipe portion and a connecting seat, the connecting seat is fixedly connected to the valve seat, the first connecting pipe portion and the second connecting pipe portion are fixedly connected to the connecting seat, the inner wall of the valve seat cooperates with the outer wall of the valve needle, the valve seat defines the inner edge guide section.
 8. The electronic expansion valve according to claim 8, further comprising a nut assembly, wherein the nut assembly comprises a nut and a nut connecting portion, the nut is fixedly connected to the nut connecting portion, the nut connecting portion is fixedly connected to the connecting seat, the nut further comprises a nut guide section, the inner wall of the nut guide section cooperates with the outer wall of the valve seat.
 9. The electronic expansion valve according to claim 2, further comprising a valve seat, a first connecting pipe portion and a second connecting pipe portion, the first connecting pipe portion and the second connecting pipe portion are fixedly connected to the valve seat, the inner wall of the valve seat cooperates with the outer wall of the valve needle, the valve seat defines the inner edge guide section.
 10. The electronic expansion valve according to claim 9, further comprising a nut assembly, wherein the nut assembly comprises a nut and a nut connecting portion, the nut is fixedly connected to the nut connecting portion, the nut connecting portion is fixedly connected to the valve seat.
 11. The electronic expansion valve according to claim 2, wherein the inner diameter of the outer edge guide section is between about 0.02-about 0.15 mm greater than the inner diameter of the inner edge guide section.
 12. The electronic expansion valve according to claim 1, wherein the valve needle support portion comprises a valve needle support washer or a suspension engagement portion or a sleeve washer, the valve needle support washer or the suspension engagement portion or the sleeve washer is abutable against the matching portion of the valve needle sleeve. 